Electrophysiologic and hemodynamic effects after aminophylline endovenous administration in man

1987

Cardiologia (Rome) 32(9): 1005-1007

Electrophysiologic and hemodynamic effects after aminophylline endovenous administration in man

Recent studies found that aminophylline iv induces life-threatening arrhythmias and sudden death. The purpose of this study was to evaluate the effect of iv aminophylline on cardiac arrhythmias on 12 patients mean age 58 years that underwent both hemodynamic and electrophysiologic testing with programmed ventricular stimulation. After control studies, aminophylline was infused using an iv bolus of 5.6 mg/kg after which 0.9 mg/kg/hour was delivered by iv infusion. After aminophylline administration a blood sample was taken to document aminophylline concentration. Drug levels ranged from 9.5-12.0 mg/l. Before and after drug administration were measured the following parameters: left ventricular systolic pressure (LVSP), left ventricular filling pressure (LVFP), mean arterial pressure (MAP), left ventricular dP/dt and totale vascular resistences (TVR). Programmed ventricular stimulation was performed at 600 and 462 ms cycle length and single and double extrastimulus were delivered at the apex of right ventricle. Ventricular repetitive responses were 3 or more beats of intraventricular reentry. Effective refractory period of right ventricle did not change after aminophylline. In 9 patients repetitive ventricular responses were induced after aminophylline. LVSP and MAP were not modified. LVFP and TVR dropped respectively 31.4 and 10.8%. LV dP/dt and Co increased respectively 28.8 and 17.9%. Our findings suggest that therapeutic doses of aminophylline induce ventricular electrical instability in patients already presenting with life-threatening arrhythmias. However aminophylline produces an positive inotropic effect.